1. Field of the Invention
The present invention generally relates to threshold bars and other floor and wall covering transition elements.
2. Discussion of Prior Art
Threshold bars are elements fixed to the floor of residential, office, or industrial premises, at the junction of two floors of different natures or of different levels. A threshold bar has both a functional and an aesthetic purpose. It protects adjacent floor edges and masks their irregularities while defining a clear and straight separation line.
Other transition elements are used between the limit of a floor and a wall, also for functional and/or aesthetic reasons. For example, with wood flooring, it is desirable to leave a gap between the limit of the floor and the wall, to avoid expansion problems. The transition edging hides the gap and protects the edge of the floor.
Transition elements are also used against walls, for example, in the form of baseboards or beading for separating wall coverings.
FIG. 1 is a perspective cross-section view of part of a known threshold bar 2, called a threshold bar with guide rail, in position on a floor 11 on which floor coverings of different heights, respectively 12 and 13, for example, a fitted carpet and a tile, are deposited. Threshold bar 2 has a slightly convex visible upper portion, that may itself be painted or totally or partially covered with a material to give it any desired appearance. The lower portion of bar 2 comprises protruding ribs 21 and 22 defining, together and with lower portion 23 of bar 2, a longitudinal guide rail 24. Head 31 of a nail 32 may be inserted into this guide rail. This nail is intended to be driven into a hole formed in floor 11 into which a bushing 33 may or may not have been previously introduced.
FIG. 2 is a perspective view of a nail 3 illustrating a nail head shape particularly well adapted to guide rail 24 of bar 2. Head 31 has the shape of a half-cylinder perpendicular to a shank 32 of the nail and flattened on the side opposite to this shank. Half-cylinder 31 forms a slider capable of being slid in guide rail 24. Such a slightly elongated shape of sliders 31 enables a rotation of the nail head and thus of shank 32 of nail 3 to be avoided in a plane comprising the longitudinal guide rail axis. Thus, the shanks cannot lean in the guide rail during the driving-in phase. In the example of FIG. 3, nail 3 is a plastic “nail plug” provided with anti-wrenching fins 33, intended to be directly driven into a hole made in the floor.
The system of FIGS. 1 and 2 has the advantage of being easy to fit. Indeed, it is sufficient to prepare aligned holes in the floor without it being necessary to have precise intervals between them. A number of nails 3 corresponding to the number of holes are placed in the guide rail, after which the nails are installed by sliding them to be aligned with the corresponding holes, and the bar is pressed down, driving in the nails. This driving-in may be simply performed by stepping on the bar.
In the example of FIGS. 1 and 2, lower guide rail portion 23 is preferably V-shaped with a bearing edge 25 (FIG. 1) substantially bearing on the center of the planar upper surface of head 31 of nail 3. Further, the space between the opposite lips of ribs 21 and 22 is greater than the diameter of shank 32 of nail 3. Thus, once the nail has been placed in position, and until it has been fully driven in, the threshold bar may rotate slightly around the nail heads, the rotation axis corresponding to bearing edge 25. This enables a positioning and fixing for different heights of the interval between floor coverings 12 and 13. As shown in FIG. 1, the internal walls of ribs 21 and 22 have, towards their extremities, a shape complementary to the curve of slider 31. The angle of the V defining bearing edge 25 is preferably selected so that, when the threshold bar is positioned in an extreme of inclination, there is a simultaneous bearing of the nail shank against one of the lips of ribs 21, 22 and of the upper half of the nail head against one of the sides of the V.
A threshold bar such as illustrated in FIG. 1 is described in European patent 0588734 of the applicant.
Other threshold bars with guide rails are known, which define, in their lower surface, a guide rail adapted for the head of a screw-nail or nail plug. For example, the nail heads may have any desired cylindrical shape, for example, with a circular cross-section. Similarly, in a simple embodiment, the nail shanks may be threaded.
A structure inverse to that of FIG. 1 may also be contemplated, in which the bottom 23 of the guide rail is substantially planar and wherein it is the head 31 of the nail that has a convex V shape, the edge of the V defining an axis of rotation.
Drilling into the floor or the wall on which the transition element is to be fixed is not always possible or desired. Adhesive transition elements are then used on the surface of the covering.
FIG. 3 is a perspective view of part of another threshold bar, called a glued threshold bar. Threshold bar 4 is, like threshold bar 2 of FIG. 1, intended to mask the separation line between two floor coverings 13 and 12 (for example, of unequal height). The external aspect of threshold bar 4 is similar to that of threshold bar 2 and thus comprises a slightly convex visible upper portion, which may itself be painted or covered with a material to give it any desired appearance. Threshold bar 4 is fixed by gluing. To achieve this, two fillets 41 and 42 of glue are pre-positioned on the lower surface of bar 4 close to the longitudinal edges thereof. Before fitting, these fillets are generally protected by a peel-off paper strip which is removed by the user to apply the threshold bar.
A disadvantage of glue fillets is that they generate an extra thickness which adversely affects the appearance. Further, as time goes by and with the passing of people, glue fillets tend to flow, which generates a shift of the threshold bar or a cohesive failure of the adhesive.
Solutions comprising the application of a double-sided adhesive under a threshold bar for its fixing are also known. Such a solution is however only applicable to planar threshold bars. Indeed, such an adhesive strip does not adhere if it is placed under a threshold bar of variable height, for example, convex. Accordingly, it cannot be used for bars capable of adapting to floor coverings of variable or unequal height.
It would be desirable to be able to simply and reliably glue a convex threshold bar, possibly with a level adjustment.
Document GB-A-2425785 describes a profile system for joining together the edges of adjacent panels. This system comprises a rear component part supporting an intermediate connecting member and a front component part having an intermediate connecting member cooperating with that of the rear part. Two surfaces of the front part comprise adhesive strips.